Chosen Solution
Problem - no start up! Retinal display cracked so screen not working. I have been using a HDMI to external monitor. I was in the process of updating the OS… (probably to Sierra from El Capitan) Laptop turned off half way through update. Now I can see light coming from the sides of the screen but nowhere else. HDMI to external screen doesn’t register on external screen when starts up. I also tried MINI DP TO HDMI to same external display. I took cover off and cleaned it out pretty good and it’s still doing the same thing. Laptop doesn’t turn off when I close the lid but lights turn off. Please let me know if you have any ideas. Thank you!
No easy answer here ;-{ Without a working internal display we just don’t know whats happening. During the update process the system will reboot a few times on its own as it is also updating the systems firmware. So did the system get stuck in that phase of the update or because of the firmware update the external monitor is not registering. I would take the system to an Apple Store and ask them for an estimate explain you’ve been using the external monitor for a while without any problems so they don’t over focus on the broken display. Lets see what they say and what the costs will be. Ideally, they should quote you a bench fee plus parts, the parts will be the clue if they say logic board then you have to decide if you want to put that much into the system (between the display & logic board).
